Method of making glass articles



Oct. 26, 1943. 3 A. H. STEWART METHOD OF MAKING GLASS ,AR'I'iCLES Fil ed Nov. 8. 1941 Patented Oct. 26, 1943 UNITED STATES PATENT OFFICE2,333,076 METHOD or MAKING GLASS ARTICLES Andrew H. Stewart, Beaver,Pa., assignor to The Phoenix Glass Company, Monaca, Pa., a corporationof West Virginia Application November 8, 1941, Serial No. 418,307

1 Claim. (Cl. 49-85) This invention relates to glassware manufacture andmore particularly to a method for making glass articles such, forexample, as the light enclosing troughs used on fluorescent lightfixtures, although it will be apparent from the following descriptionthat the invention is also adapted to the manufacture of a wide varietyof other articles.

' Heretofore, the difficulty of blowing articles of this size and typehas compelled their manufacture by bending flat sheets, with theresulting limitation in the types of glass fromwhich such articles couldbe made. An object of this invention is to provide a method ofmakingglass articles of the type set forth by a blowing operation.

This and other objects which will be apparent to those skilled in theart are accomplished by this invention, one embodiment of which is shownin the accompanying drawing, in which Fig. l is-an elevation, partly insection, of a glassware making machine for making glass lighting troughsin accordance with my improved method.

Fig. 2 is an elevation of the apparatus shown in Fig. l at thecompletion of a molding operation, and

Fig. 3 is an enlarged section showing a portion of the blow mold' andtable.

In the particular embodiment of the invention which is illustrated inthe accompanying drawing, a mold table Ill is preferably provided with arecess I l in the top surface for receiving molten glass. The face ofthe depression is lined with a layer I! of heat insulating materialwhich is at the same time a poor conductor of heat and will not mar theglass. Carbon will be found satisfactory as well as other materials wellknown to those skilled in the art. Air yents 13 extend through the tableto the glass supporting surface.

A mold it having a manifold l5 and vents l6 connecting the manifold withthe mold cavity is mounted for vertical movement on a. hollow plunger lladapted to be raised and lowered by a piston I8 in a cylinder l9operated by fluid pressure through flexible'c'onnecting lines 20 and 2|.The cylinder is supported in the outer end of an arm 22 mounted forrotation on any suitable support or standard 23. The manifold I5 isconnected through the hollow plunger and ilexible line with a source ofvacuum (not shown) In operation, a layer or sheet of molten glass isspread evenly over the surface of the mold table, in the recess ll whensuch recess is formed in the table, either by a flow device or with aladle (not shown). The glass is spread,- out in a flat even sheet byrolling or in any other desired manner. If necessary, heat can beapplied to the glass on the table to bring it to the desired moldingtemperature. During the spreading operation any excess glass can bepushed over the edge into a suitable receptacle.

When the glass is at the proper molding temperature a mold ll is droppedin place on the glass sheet, a sharp edge 25, see Fig. 3, on the edge ofthe mold cutting into but not entirely through the glass so as to sealthe mold cavity against leakage of air around the edge and at the sametime forming-a breakage line for subsequently removing excess glass fromthe finished articles. Preferably, the entire weight of the mold doesnot rest on the molten glass, but only sufficient to provide therequisite seal and trim line.

As soon as the mold is in position the vacuum is applied through theline 24 to raise the 818551 to the lower face of the glass through avalve 26 in line 21 extending through the mold table, and the glass thusblown against the mold wall.

The excess glass is then trimmed from around the mold and, with vacuumstill applied to hold the glass in the mold, the latter is lifted fromthe mold table by the piston and cylinder l8 and I9 and swung over areceiving table 28 or other surface such a a carrying in paddle or thelike on which the blown article 29 is deposited and then placed in alear.

Fig. 1 shows a manifold 3| enclosing the vents l3 to provide a chamberin which an inert gas, steam, carbon dioxide or the like at atmosphericor greater pressure may be applied to the vents, but obviously this isnot necessary.

Clamps 32, shown in Fig. 1 conventionally, are employed for holding themold in position when blowing pressure is applied.

It will be apparent that the invention can be variously modified andadapted within the scope of the appended claim.

I claim:

The method which comprises applying molten glass to a supportingsurface, positioning a mold over the glass on said surface, decreasingthe pressure in said mold and increasing the pressure between said glassand said surface during the molding operation.

ANDREW H. STEWART.

